Molding apparatus



Oct. 7, 1958 Filed Sept. 5, 1957 L. L. .JOHNSTON 2,854,710

MoLDNG vAPPARATUS 3 Sheets-Sheet 1 INVENTOR Loyal L. Johnston Oct. 7, 1958 L. L. JOHNSTON v MOLDING APPARATUS Filed sept. 5, 1957 3 Sheets-Sheet 2 IVENTOR Loyal L. Johnston Oct. 7, 1958 Filed Sept. 5, 1957 Fig .7.

L l l I p." l l MOLDING APPARATUS L. L. JHNs-TON 2,854,710

3 Sheets-Shed'I 3 55 lau l 5 I4 36 l 'a I6 i I3 34 .I i 22 l ZOn; E 2l l I Figo.

. V lf O G lI f G J -v ,z O O' INVENTOR Loyal L. Johnston @aw/YW United States Patent() MoLDING APPARATUS Loyal L. Johnston, Zelienople, Pa., assigner to Herman Pneumatic Machine Company, Pittsburgh, Pa., a corporation of Pennsylvania Application september s', 1951, seal No.u 682,251 s claims.. (cl. zz-16) the ask to form a' mold. The invention has to do with the'utilization of the ask itself as a measuring container determining the volume of uncompacted mold forming material introduced into the llaslcv for formation of the mold so that when the mold forming material is compacted a mold of desired size is made.

The present invention may be applied to apparatus for forming molds for centrifugal castings of the type `shown in my Patent No. 2,449,900. Such apparatus comprises either one flask or a plurality of tlasks',in'batteryL for example, I shall here refer to one flask. The ask is rotatably carried by a cradle which in turnis mounted for movement between a position in which the axis of the ask is generally upright and a position in which the axis of the flask is generally horizontal. The cradle carries' means for rotating lthe ilaslc. At the beginning of the cycle the flask is disposed in generally upright position and its lower end is closed by mold forming material retaining meanswhereupon finely divided mold forming material, such, for example, as sand, is introduced into the ask through the upper end thereof. Rotation of the flask is commenced and the ask is moved to generally horizontal position. The mold forming material retaining means is moved to inoperative position, a mandrel is introduced into the flask to compact the mold forming material, the mandrel is withdrawn and molten material, for example, iron, vis then introduced into the mold and centrifugally cast to make, for example, a length of soil pipe. After the casting has solidified the liask is returned `to its generally upright position and the casting is ejected therefrom whereupon the mold forming material retaining means is again disposed in its operative position to close the lower end of the flask and the cycle is repeated.

It is important that the proper amount of uncompacted mold forming material be introduced into the ask to form when compacted to the proper degree a mold of desired size. The problem of how most efciently and rapidly to measure the mold forming material has existed for many years and has not been satisfactorily solved prior to the present invention. At one time the mold forming material was measured before being introduced into the flask. The procedure was very uneconomical, requiring both additional apparatus and additional labor. The quantity of uncompacted mold forming material required to form the mold will usually approximately lill the flask but the ask cannot be relied upon as a measuring container for the mold forming 4material because the volume of the flask and the volume of the uncompacted mold forming material required to form a mold of desired size when compacted to the proper degree vary with such factors as the size of the enlargement or enlargements at one or both ends of the flask for the formation r ICC of a bell or bells on the pipe being cast, the length of the casting, whether the casting is to be of standard or other wall thickness, etc.

I proposed in my Patent No. 2,598,554 a solution to the problem involving the selection of a ask whose internal diameter bears a particular relationship to the internal diameter of the mold to be formed. However, such selection of a ask is not always practicable. Under certain conditions the mold forming material may be compacted to a greaterv or less extent than might be considered normal; also, the number and size of the enlargement or enlargements vor at one or both ends of the ask introduce a further complication. 'Y

l have finally discovered a very simple but highly effective way of utilizing the ask itself to measure the mold forming material to be used in forming a mold in the iiask. I provide means at the end of the ask opposite the end through which the mold forming material lill is introduced displacing a predetermined part of the volume of the ask so that the volume of the mold forming material which is introduced into the flask is determined by the remainder of the volume of the llask whereby to assure the presence in the ask of the proper volume of uncompacted mold forming material to form when compacted a mold of desired size. Such volume displacing means may be of various sizes and shapes depending upon the particular ask being used and the par; ticular specifications as to degree of compacting the mold forming material, etc.

The displacing means is preferably carried by the closure means for the end of the flask opposite the end through which the mold forming material is introduced; l preferably provide means for moving the closure means into and out of a position in which the closure Vmeans and the displacing means carried thereby are operative with respect to the flask, the end of thge ask at which such means are disposed beingopen when the closure means and the displacing means carried thereby are moved out of said position. Normally the flask will have a radial enlargement at at least the end thereof at which the closure means and the displacing means are disposed and the displacing means when operative will be disposed at least partially within the radial enlargement.

Other details, objects and advantages of the invention will become apparent as the following description of a present preferred embodiment thereof proceeds. (l

ln the accompanying drawings I have shown a present preferred embodiment of the invention in which:

Figure 1 is an end elevational view of molding apparatus, the mold forming material retaining and displacing means being shown in inoperative position;

Figure 2 is a side elevational view of the molding apparatus shown in Figure 1 the mold forming material re-v taining and displacing means being shown in inoperative position in solid lines and in operative position in chain lines;

Figure 3 is a fragmentary elevational view, partly in vertical cross section and to enlarged scale, of a portion of the apparatus shown in Figure 1 but with the mold forming material retaining and displacing means swung tp their downward or operative positions, the mounting means, cradle and asks being omitted for clarity;

Figure 4 is a fragmentary top plan view showing a portion of the mechanism shown in Figure 3; i 1".'

Figure 5 is a vertical cross-sectional view taken on the line V-V of Figure 4;

Figure 6 is a vertical cross-sectional view taken 'loathe line VI--VI of Figure 5; 1

Figure 7 is a fragmentary elevational view to -enlaged scale and with a portion in vertical cross section off-part l of the apparatus shown inl Figure 2, the mold vforming material retaining and displacing means being shown in operative position in solid lines and in inoperative position in chain lines; and

Figure 7 is a plan view of the apparatus shown in Figure 7 but for clarity omitting the showing of the flask end.

The apparatus shown is of the general type of that of my Patent No. 2,449,900. 1 provide mounting means designated generally by reference numeral 2 in which is mounted -a cradle 3 for movement between generally upright position and generally horizontal position as disclosed in my said patent. In the drawingsthe cradle 3 is shown in. generally horizontal position. Rotatably mounted on the cradle 3v are two parallel asks 4 each driven through a belt S by a motor 6 also carried by the cradle. Parts of the apparatus not necessary to the functioning of the invention are not shown.

The cradle 3 carries atop each of the flasks 4 adjacent an end thereof a bracket designated generally by reference numeral 7, the two brackets being disposed side by side but spaced apart. Each bracket has opposed arms 8 spaced apart'and reaching toward the end of the ask. Journaled in the arms 8 of each of the brackets 7 is a shaft 9. Fixed to eachshaft 9 is a generally L-shaped arm 16. Each arm 10 is fixed to the corresponding -shaft 9 at one end of the arm and when the arm is in operative position it projects toward the end of the flask and downwardly to a position intersecting the axis of the flask as shown in Figure 7. The free extremity of each arm 10 is formed as a carrier 11.v While in the-form shown the carrier 11 is integral with the arm it may be `separately a position relatively remote from the end of the ask and alongside but substantially spaced from the flask.

Bolted to each carrier 11 by bolts 12 is a plate 13. Threaded through the plate 13 are three positioning screws 14 each provided with a lock nut 15 and adapted to be adjustably positioned so that their extremities 16 serve as stops or positioning members to precisely determine the position of a mold forming material retainer designated generally by reference numeral 17 and comprising a plate-like portion 18 welded as shown at 19 to a generally cylindrical portion 20 telescoping within the carrier 11. The outside of the generally cylindrical portion 20 is somewhat convexly formed or curved as shown at 20a to permit relative angular adjustment between the retainer and the carrier. Three bolts 21 pass through openings 22 in the plate 13 and are threaded into the cylindrical portion 20 of the mold forming material retainer 17, the screws 14 and 21 being cooperatively operable to move the retainer 17 relatively to the carrier 11 in a direction which when the carrier is in position at an end of the flask is generally parallel to the axis of the iiask to a selected one of a plurality of positions to substantially close the end of the ask. When the retainer 17 is in operative position the face of the portion 18 thereof opposed to the end of the ask just clears the end of the flask by a very small fraction of an inch, perhaps one-sixteenth of an inch, to permit turning of the fLask while the retainer does not turn, yet preventing the mold forming material in the ask from walling out. To prevent substantial leakage of mold forming material while filling the flask and tilting it to generally horizontal position I preferably provide a projection 18a on the retainer which is of circular shape and of very slightly smaller external diameter than the internal diameter of the extremity of the ask which substantially'lls the end of the flask and projects into the end of 'the llask. The projection 18a, may, for example, be a one-half inch thick circular plate whose external diameter is one-eighth shown in Figure 7.

4 inch less than the internal diameter of the extremity of the ask, providing a circumferential clearance between the projection 18a and the inside of the flask of onesixteenth inch.

Intermediate the upper portions of the flasks the cradle carries a cylinder 23 arranged with its axis generally parallel to the axes of the flasks in which operates a piston with which is connected a piston rod 24 carrying at its outer end a toothed rack 2S. The teth 30 of the rack 25 point upwardly, the rack being supported upon a supporting and guiding roller 26 for back and forth movement as the piston is operated in the cylinder 23 by fluid under pressure controlled by suitable valves as well known to those skilled in the art.

Et has been explained above that the two shafts 9 are coaxial. Operatively interposed between the shafts 9 and connected with each thereof by a ilexible coupling 27 is a shaft 28 to which is fixed a pinion 29 in mesh with the teeth 30 of the rack 25. Thus movement of the piston in the cylinder 23 causes movement of the rack, which movement through the pinion 29 turns the shaft 28, which shaft through the flexible couplings 27 turns the shafts 9 to pivotally move the arms 10, carriers 11 and retainers 17 between operative and inoperative positions.

The ends of the arms 8 have upwardly facing positioning faces 31 and the arms 10 carry lateral projections 32 having positioning stops 33 adjustably mounted thereon and adapted to come to rest uponthe faces 31 when the retainers 17 are inoperative position. Thus the retainers`c`an be quickly shifted between accurately disposed operative positions substantially closing the endsof the asks and inoperative positions remote from the ends of 111e flasks permitting discharge of the castings therefrom or permitting introduction of the mandrels for compacting the mold forming material.

The projection 18a of each retainer 17 carries at its A outer face displacing means designated generally by reference numeral 34 shown as being of generally hat shape, in'cluding a base portion 35 and a projecting portion 36 whichin the form shown is of generally frusto-conical shape. The particular size and shape of the displacing means may vary Widely depending upon the volume to be displaced, the size and-shape of the radial enlargement if any at the end of the ask, the degree of compacting of the mold forming material specified and other factors. However, the displacing means 34 displaces a predetermined part of the volume of the tiask so that the volume f the mold forming material which is introduced into the flask is determined by the remainder of the volume of the flask whereby to assure the presence in the ask of the proper volume of uncompacted mold forming material to form when compacted a mold of desired size.

The displacing means 34 may be fastened to the retainer in any suitable Way, as, for example, by bolts 37 Thus one displacing means may easily be removed and replaced by other displacing means of a different displacing capacity and/'or shape. The mechanism allows the completely formed mold to actually be shifted in or out with relation to the ask.

While I have shown and described a present preferred embodiment of the invention it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied within the scope of the following claims'.

I claim:

l. Molding apparatus comprising a ask adapted to receive inely divided mold forming material, means for rotating the flask to centrifugally compact the mold forming material against the inner surface of the flask to at least partially form in the ask a mold of the mold forming material, the ask itself serving as a measuring container determining the volume of uncompacted mold forming material introduced into the flask through an end thereof for formation of the mold, closure means blocking egress of mold forming material through the opposite end of the flask and means at said opposite end of the flask displacing a predetermined part of the volume of the flask so that the volume of the mold forming material which is introduced into the first mentioned end of the flask is de termined by the remainder of the volume of the flask whereby to assure the presence in the flask of the proper volume of uncompacted mold forming material to form when compacted a mold of desired size.

2. Molding apparatus comprising a flask adapted to receive finely divided mold forming material, means for rotating the flask to centrifugally compact the mold forming material against the inner surface of the flask to at least partially form in the flask a mold of the mold forming material, means for moving the flask between a position in which its axis is generally vertical and a position in which its axis is generally horizontal, the flask itself when in the first mentioned position serving as a measuring container determining the volume of uncompacted mold forming material introduced into the flask through the upper end thereof for formation of the mold, closure means blocking egress of mold forming material through the opposite end of the flask and means at said opposite end of the lflask displacing a .predetermined part of the volume of the flask so that the volume of the mold forming material which is introduced into the first mentioned lend of the flask is determined by the remainder of the volume of the flask whereby to assure the presence in the flask of the proper volume of uncompacted mold forming material to form when compacted a mold of desired size.

3. Molding apparatus comprising a flask adapted t-o receive finely divided mold forming material, means for rotating the flask to centrifugally compact the mold forming material against the inner surface of the flask to at least partially form in the flask a mold ofthe mold forming material, the flask itself serving as a measuring container determining the volume of uncompacted mold forming material introduced into the `flask through an end thereof for formation of the mold, closure means blocking egress of mold forming material through the opposite end of the ask and means carried by the closure means displacing a predetermined part of the volume of the flask so that the volume of the mold forming material which is introduced into the first mentioned end of the flask is determined by the remainder of the volume of the flask whereby to assure the presence in the flask of the proper volume of uncompacted mold forming material to form when compacted a mold of desired size.

4. Molding apparatus comprising a flask adapted to receive finely divided mold forming material, means for rotating the flask to centrifugally compact the mold forming material against the inner surface of the flask to at least partially form in the flask a mold of the mold forming material, the flask itself serving as a measuring container determining the volume of uncompacted mold forming material introduced into the flask through an end there- 0f for formation of the mold, closure means blocking egress of mold forming material through the opposite end of the flask, means carried by the closure means displacing a predetermined part of the volume of the flask so that the volume of the mold forming material which is introduced into the first mentioned end of the ffask is determined by the remainder of the volume of the flask whereby to assure the presence in the flask of the proper volume of uncompacted mold forming material to form when compacted a mold of desired size and means for moving the closure means into and out of a position in `which the closure means and the means carried thereby are operative with respect to the flask, the second mentioned end of the flask being open when the closure means and the means carried thereby are moved out of said position.

5. Molding apparatus comprising a flask adapted to receive finely divided mold forming material, means for rotating the flask to centrifugally compact the mold forming material against the inner surface of the flask to at least partially form in the flask a mold of the mold forming material, the flask itself serving as a measuring container determining the Volume of uncompacted mold forming material introduced into the ilask through an end thereof for formation of the mold, the flask having a radial enlargement at at least the opposite end thereof, closure means blocking egress of mold forming material through said opposite end of the flask and means disposed at least partially within the radial enlargement at said opposite end of the flask displacing a predetermined part of the volume of the flask so that the volume of the mold forming material which is introduced into the first mentioned end of the flask is determined by the remainder of the volume of the flask whereby to assure the presence in the flask of the proper volume of uncompacted mold forming material to form when compacted :a mold of desired size.

References Cited in the file of this patent FOREIGN PATENTS 341,673 Great Britain Jan. 22, 1931 

